DE4130919C2 - Process for the preparation of 2-aminoethyl esters of methacrylic acid - Google Patents

Description

The present invention relates to a method for producing 2- Aminoethyl esters of methacrylic acid (hereinafter referred to as 2-AEMA net) by reacting methacrylic acid with an aziridine compound.

The 2-AEMA made according to the invention are useful compounds gene as raw materials for dispersants, flocculants, coagula agents, paper additives that are used as retention aids medium, drainage aids, strength aids, thickeners medium, adhesive, chelate resin, ion exchange resin, resin for enhanced Oil production, photoresist material, enzyme carrier, antibacterial resin and modifying and processing aids used in the manufacture of fibers, plastics, paints, inks, papers and other products products are used.

To produce 2-AEMA is, for example, one in US Pat. No. 3,336,358 described method known. According to this procedure, first Methacrylic acid (hereinafter referred to as MA) in a saturated (or unsaturated) aliphatic hydrocarbon solvent with an aziridine compound (hereinafter referred to as Az) for the reaction brought. Then an inorganic acid is made to the 2-AE Given MA and then the inorganic salt of 2-AEMA separated.

The method described in US Pat. No. 4,500,728 is known as a Process that improved compared to the above process Yields of the desired product achieved. With this procedure 2- Isopropenyl-2-oxazoline (hereinafter referred to as IPO) an aqueous Solution containing an acid described in more detail is added so 2- To maintain AEMA high purity.

However, the method of US Pat. No. 3,336,358 shows the following share on: low selectivity regarding the desired product, the is called 2-AEMA, and the formation of large amounts of by-products. Since 2- AEMA have a double bond, some shares in 2- AEMA converted to polymer when the inorganic acid was added becomes.

The process of US-PS 45 00 728 meanwhile requires a number of Operations for the production of IPO, that is, the raw material.  

Therefore, if you compare the yield of 2-AEMA with regard to the Considered starting materials used by IPO, is the Aus loot extremely low due to the large number of operations where result from high manufacturing costs.

The object of the present invention is a method for the production of high-purity 2-aminoethyl esters of methacrylic acid, in which the manufacturing costs are reduced.

In order to achieve these goals, the inventors have the reaction conditions extensively studied for MA and Az for the production of 2-AEMA, whereby a process could be produced which had high yields achieved with 2-AEMA at low manufacturing costs.

The invention thus relates to a process for the preparation of 2- Aminoethyl esters of methacrylic acid by reacting methacrylic acid re with an aziridine compound, which is characterized in that the reaction in a water and aqueous solvents selected reaction solvent, in a proportion of 5 to 90 wt .-% Water, based on the total weight of the reaction mixture, at one Performs temperature in the range of 10 to 100 ° C.

According to the invention, 2-AEMA include in addition to 2-aminoethyl ster by the implementation of a molecule MA and a molecule Az is formed, esters formed by the further reaction of Az with the Amino group formed by 2-aminoethyl esters, that is, by Implementation of 1 molecule of MA and a large number of molecules of Az esters are also useful compounds for making the above mentioned industrial products.

In the method according to the invention, water or an aqueous solution solvent with a high dielectric constant as a reaction solvent means used. Accordingly, the implementation is conditional conditions in which ionization proceeds smoothly, thereby reducing the Yield of 2-AEMA based on the amount of aziridines used bond is improved. Since the 2-AEMA formed continues as the salt of Methacrylic acid or inorganic acid will be stabilized Yield improved.  

Water or an aqueous solvent which in the invention Process used as the reaction solvent is less expensive as a saturated or unsaturated aliphatic hydrocarbon Solvents, for example n-hexane, which is used in the conventional process ren is used as a reaction solvent. Consequently, Her service costs can be reduced. The process also enables Preparation of 2-AEMA with improved yields compared to that conventional processes. Another advantage is that 2-AE- MA high purity from the reaction solution using a very simple Working method can be obtained.

The process according to the invention for producing 2- Aminoethyl esters of methacrylic acid described in more detail.

The selectivity mentioned herein is the ratio of Az (aziridine compound) used to produce a desired product to Az used and is reported as P _A / F _A × 100, where F _{A is} the number of moles of Az and P used _A indicates the number of moles of Az in the 2-AEMA produced.

For Az, although there are no particular restrictions in this regard stands, ethyleneimine, propyleneimine, hydroxyethylethyleneimine, cyanoethy preferred ethyleneimine and aminoethylethyleneimine.

With regard to the reaction solvent, water is preferred, it can be but an aqueous solvent can also be used. The watery Solvent is a mixture of water and a solvent, that can be dissolved in water in any ratio. For example, who the methanol, ethanol, isopropyl alcohol, acetonitrile, acetone, dimethyl sulfoxide, dimethylformamide, dioxane and tetrahydrofuran used.

The proportion of water in the total reaction mixture is in the range of 5 to 90% by weight. The proportion of water means that Proportion of the weight of water to the total weight of the used materials, that is MA and Az and solvent, that is what water or aqueous solvent.

If the water content is less than 5% by weight, MA or Lö is  solvent that can be dissolved in water in any ratio Main percentage of solvent in the reaction mixture. This suppresses ionization so that the formation of a stable salt is suppressed by 2-AEMA and MA. This results in a reduced Selectivity at 2-AEMA. On the other hand, if the proportion of water is 90% by weight exceeds, the dilution of the starting material increases where is reduced by the reaction rate, so that a decrease productivity. So using Water in excess or reduced amounts with respect to the above areas mentioned unfavorable results.

If one designates the number of moles of MA used in the reaction mixture as F _M and the number of moles of Az used as F _A , the molar ratio of F _M to F _{A is} in the range from 1/2 to 20/1, preferably from 2/1 to 10/1. If the molar ratio of F _M to F _{A used is} less than 1/2, free MA as a starting material in the reaction mixture decreases significantly since the amino group of the 2-AEMA and MA produced form a salt. This causes the production of 2- AEMA in reduced amounts and a reduction in the selectivity. On the other hand, if the ratio of F _M to F _{A is} larger than 20/1, large amounts of MA have remained unreacted at the time of completion of the reaction. Therefore, it takes a lot of time to remove MA during cleaning, causing a reduction in productivity.

As a concrete method regarding the implementation of MA with Az, it is whether there is no particular restriction in this regard, desirable, the molar ratio of acid to amine in the reaction mixture so re gulate that this is not below 1.5. The reason for this is in that free MA must be present throughout the process in order to Promote implementation. However, if a basic substance, for example se an amine, in the reaction mixture, MA and the basic Substance ionically bound to form a salt of MA. This Salt takes part in the implementation to form the desired product not part, which slows down the reaction rate.

In order to carry out the implementation quickly, the following two measures methods listed.  

In the first method, larger amounts of MA with respect to amine are used seen so that free MA is present in the reaction mixture, even if MA reacted with all of the amine in the reaction mixture and a Salt forms. This means that implementation is progressing with this method by maintaining the molar ratio of MA to amine in the reak tion mixture of at least 1.5.

In the second method, an inorganic acid, for example Sal nitric acid, the reaction mixture added to the MA in the MA and to replace amine formed salt, thereby forming nitrate. This allows the creation of free MA and the implementation to continue. This means that the implementation is carried out with this method Maintaining the ratio of one equivalent A of free MA to a base equivalent B of Az, i.e. A / B, of at least 1.5 (this method is particularly effective when the molar ratio of MA used to amine does not exceed 1.5).

For example, a preferred implementation is carried out by trop introducing Az into an aqueous solution containing MA tel in the presence of a polymerization inhibitor, for example hydro quinone, or by introducing MA together with Az into an aqueous Solvent.

The concentration of MA and Az in the reaction mixture is preferred as within the range of 10 to 95 wt .-%. A low con concentration of less than 10% by weight results in a reduction in the Productivity. In contrast, with a high concentration of more than 95% by weight Az, which promotes the reaction, essentially in MA ge solves. This suppresses the ionization, so that the formation of a stable len salt of 2-AEMA and MA is inhibited. Hence the selectivity reduced.

The temperature is in the range from 10 ° C to 100 ° C, preferably between 20 ° C to 80 ° C. A temperature of less than 10 ° C results in a reduction in the reaction rate and there through in a reduction in productivity. On the other hand, one promotes Temperature of more than 100 ° C the formation of by-products. At for example, 2-AEMA becomes as shown in the following formula (1)  Amide isomerizes, reducing selectivity.

Formula 1)

Regarding the reaction system, the pressure does not need to be particularly regular to be met. However, if an aqueous solvent is a solution with contains tel, whose boiling point is low, the implementation under Pressure.

If unreacted MA is removed, a solution of the anorga African acid salt of the 2-AEMA produced can be used. Around after the reaction of MA with Az in an aqueous solvent Obtaining solution of the inorganic salt of 2-AEMA becomes an anor ganic acid, for example hydrochloric acid added and then unreacted MA using a solvent that is insoluble in water is extracted, such as benzene, toluene and chloroform separates.

The following examples and comparative examples serve only the purpose of illustration and are in no way intended to limit the scope of the Restrict invention.

example 1

344 g MA, 387 g deionized water and 3.44 g hydroquinone as a polymer Risk inhibitors were placed in a reaction container, mixed and heated to 50 ° C. Then, while the mixture was held at 50 ° C ten g, 43 g of ethyleneimine (hereinafter referred to as EI) as Az the Mi added dropwise in about an hour to the reaction perform. Then the temperature of the reaction mixture became Completion held at 50 ° C for 4 hours to obtain 2-AEMA. The reaction solution was analyzed by liquid chromatography. The selectivity of the EI added as Az was 94.8%. The reaction area Conditions and results are shown in Table 1.  

Furthermore, 103 g of 35% aqueous hydrochloric acid solution added to the reaction solution and unreacted MA by liquid Removed liquid extraction with toluene. Then the resulting Lö solution concentrated to contain 253 g of an aqueous solution 60 wt .-% 2-AEMA hydrochloride to achieve.

Example 2

The same manufacturing process and analysis were used as in Example 1 performed, with the exception that aminoethylethyleneimine instead of the EI used in Example 1 was used. The reaction area conditions and results are shown in Table 1. According to the results Selectivity was obtained which was as high as that in Example 1.

Example 3

The same manufacturing procedures and analysis were used as in Example 1, except that a mixed solution of what water and isopropyl alcohol (50/50 by weight) instead of the in game 1 used water was used as the reaction solvent de. The reaction conditions and results are shown in Table 1 poses. This example also achieved high selectivity, similar to that in Example 1.

Example 4

The same manufacturing procedures and analysis were used as in Example 1, except that the molar ratio of MA to EI from the molar ratio (4/1) in Example 1 was changed to (1.6 / 1). The Reak Conditions and results are shown in Table 1.

As demonstrated by the results, this example achieved a high one Selectivity, similar to example 1.

Example 5

The same manufacturing procedures and analysis were used as in Example  1, except that the molar ratio of MA to EI from the molar ratio (4/1) in Example 1 was changed to (1/1). The Reak Conditions and results are shown in Table 1.

According to the results, an improved selectivity was achieved whether it was probably less than that in Example 1. In this example, unreacted MA and the amino group of the 2-AEMA produced a salt formed and stabilized, causing the absence of free MA has been. The absence of free MA seemed to decrease in the To contribute selectivity.

Example 6

The same manufacturing procedures and analysis were used as in Example 1, except that the molar ratio of MA to EI was changed from the molar ratio (4/1) in Example 1 to (2/1). The Reak Conditions and results are shown in Table 1.

This example also achieved high selectivity, similar to Example 1.

Example 7

The same manufacturing procedures and analysis were used as in Example 1, except that the molar ratio of MA to EI was changed from the molar ratio (4/1) in Example 1 to (8/1) and the An part of added MA and Az to the total weight of the reaction mixture by regulating the amount of water as a reaction solvent was set to 89% by weight. The reaction conditions and results nisse are shown in Table 1.

According to these results, despite adjusting the total weight of MA and Az used to 89% by weight, that is, the proportion of water in the reaction mixture was 11% by weight, a high selectivity aims, similar to example 1.

Example 8

The reaction temperature was set at 30 ° C. In this case  the reaction mixture as the reaction rate slows down 24 Hours at 30 ° C to complete. Furthermore, the Amount of water regulated as a reaction solvent so that the proportion of MA and Az added 50% by weight of the total weight of the reaction mixture was fraud. Except for these two differences in the Bedin The manufacturing processes and analysis were carried out in the same way as in Example 7. The reaction conditions and results are shown in Table 1.

According to these results, the time required for implementation longer compared to that in Example 1. However, a high selectivity act, similar to that obtained in Example 1 with a reaction temperature of 30 ° C, which was almost equal to the room temperature, that is, without the Mi heat especially.

Example 9

The same manufacturing procedures and analysis were used as in Example 8 performed, except that the reaction temperature to 60 ° C was discontinued. The reaction conditions and results are in Ta belle 1 shown. According to these results, a high selectivity activity similar to that in Example 8.

Example 10

Hydroxyethylethyleneimine was used as Az and the molar ratio from MA to hydroxyethylethylene amine was set at 2.5 / 1. Next the water used as the reaction solvent was 30% by weight. Except for these differences in conditions, the same Chen manufacturing process and analysis as in Example 1 performed. The reaction conditions and results are shown in Table 1.

As these results illustrate, high selectivity became similar that obtained in Example 1.

Example 11

The same manufacturing procedures and analysis were used as in Example  1, except that a mixture of aminoethyl thylenimine and EI (9/1 by weight) was used as Az. The Reaction conditions and results are shown in Table 1. How illustrated by the results was a high selectivity, similar Lich that achieved in Example 1.

Example 12

There has been a process for producing 2-AEMA with high selectivity examined. In this process, the molar ratio of MA to Az was set at 2/1 and after the reaction, an inorganic Acid, the number of moles of which was the same as that of the theoretically formed 2-AEMA, added, and then Az added, so that this with implemented unreacted MA.

Specifically, 86 g (about 1 mole) of MA, 108 g of deionized water and 86 mg of methoquinone as a polymerization inhibitor in a reaction container nis given and mixed and then heated to 50 ° C. 21.5 g (0.5 mol) of EI were added dropwise to the reaction mixture in about one hour performed while the temperature of the mixture was kept at 50 ° C, so that an implementation was carried out. Then the reaction mi 4 hours to complete at a temperature of 50 ° C held. Furthermore, 52.5 g (about 0.5 mol) of 60% nitric acid added and then 10.8 g (about 0.25 mol) of EI dropwise in about 40 mi slots introduced to implement an implementation. The reaction mi was completed at a temperature of 50 ° C for 4 hours held to receive 2-AEMA.

The reaction solution was analyzed by liquid chromatography, which Selectivity was 92.7%. It has been obtained by checking the NEN chromatogram showed that the proportion of 2-AEMA with a variety of moles of Az with respect to one mole of MA increased. The reaction condition Conditions and results are shown in Table 1.

According to the results, this example achieved, although the ultimate Molar ratio of MA to Az of 4/3 close to the molar ratio in Example 5 was the same, a higher selectivity than in Example 5. This can be due to the Be due to the fact that when nitric acid was added  de, this MA in the salt that is made from the 2-AEMA and non-rea MA was formed, replaced. Thus the free MA increased and the Implementation progressed.

Example 13

The same procedure as in Example 12 was examined by wide res adding an inorganic acid and Az so that the 2-AEMA at ho selectivity was generated even when the ratio of MA to Az was less than 1/1.

Specifically, 86 g (about 1 mole) of MA, 113 g of deionized water and 86 mg of methoquinone as a polymerization inhibitor in a reaction container nis given and mixed and then heated to 50 ° C. 26.9 g (0.625 mol) of EI were added dropwise to the reaction mixture in about one hour performed while the temperature was kept at 50 ° C, so that a Implementation was carried out. Then the reaction mixture became a temperature of 50 ° C for 4 hours to complete The result was 0.56 mol of unreacted MA. Furthermore, were 65.6 g (about 0.625 mol) of 60% nitric acid added and then 15.0 g (about 0.35 mol) of EI was added dropwise in about 40 minutes. The Reaction mixture was at a temperature of 50 ° C for 4 hours Completion kept. The process of adding nitric acid and introduction of EI was repeated four times. The total amount of introduced EI was 70.39 g (1.64 mol) and the molar ratio of MA to EI was 1 / 1.64.

The reaction solution was analyzed by liquid chromatography, which Selectivity was 60.5%. Regarding this procedure, has been proven Review of the chromatogram obtained showed that the proportion of 2-AEMA with a variety of moles of Az with respect to one mole of MA took. The reaction conditions and results are shown in Table 1 posed. As demonstrated by these results, an improvement has been made Selectivity achieved.  

Table 1

Comparative Example 1

The preparation of 2-AEMA was carried out using a reaction solution solvent that contains no water.

First, 86 g of MA, 108 g of isopropyl alcohol as a reaction solvent and 172 mg of methoquinone as a polymerization inhibitor in a reaction area Ratien given and mixed and then heated to 50 ° C. 21.5 g of egg was dropwise into the mixture in about an hour while rend the temperature was kept at 50 ° C. Then the reaction Mix at a temperature of 50 ° C for 3 hours to complete held, whereby 2-AEMA were obtained. The reaction solution was analyzed by liquid chromatography, and the selectivity of EI was 30.4%. The reaction conditions and results are in Ta belle 2 shown.  

Comparative Example 2

The same manufacturing processes and analysis as in Ver same example 1 carried out, with the exception that n-hexane instead of isopropyl alcohol was used as the reaction solvent and that the reaction temperature was set to 60 ° C. The reaction area conditions and results are shown in Table 2.

The results of Examples 1 to 13 and Comparative Examples 1 and 2 show conditions that the reaction mixture must contain water.

Table 2

It is apparent that the invention described above is in many can be varied in various ways. Such variations cannot be considered Deviation from the nature and scope of the invention are considered and all of these modifications as open to those skilled in the art are evident, are covered by the scope of the claims.

Claims (4)

1. A process for the preparation of 2-aminoethyl esters of methacrylic acid by reacting methacrylic acid with an aziridine compound, characterized in that the reaction in a reaction solvent selected from water and aqueous solvents, in a proportion of 5 to 90% by weight of water, based on the total weight of the reaction mixture, at a temperature in the range of 10 to 100 ° C. 2. The method according to claim 1, characterized in that one carries out the reaction while maintaining the ratio of C _M / C _A at least 1.5, wherein C _M the molar concentration of methacrylic acid and C _A the molar concentration of the aziridine compound be . 3. The method according to claim 1 and / or 2, characterized in that the ratio of F _M / F _{A is} in the range of 1/2 to 20/1, where F _{M is} the total number of moles of methacrylic acid used and F _{A is} the total number of moles mean used aziridine compound. 4. The method according to claim 1 or 2, characterized in that it comprises the further step:
Adding an inorganic acid to the reaction mixture and carrying out the reaction while keeping the A / B ratio at least 1.5,
wherein A is the equivalent of free methacrylic acid and B is the base equivalent of the aziridine compound in the reaction mixture.